ECLIPSE. See Astronomy.

The word _eclipse_, ἔκλειψις, signifies _failure_, namely, of light. An eclipse of the sun is caused by the intervention of the moon, at new, or in conjunction with the sun, intercepting his light from the earth, either totally or partially. An eclipse of the moon is caused by the intervention of the earth, intercepting the sun’s light from the moon, when full, or in opposition to the sun, either totally or partially. The reason why the sun is not eclipsed every new moon, nor the moon at every full, is owing to the inclination of the moon’s orbit to the plane of the ecliptic, or earth’s orbit, in an angle of about five degrees and a half; in consequence of which, the moon is generally too much elevated above the plane of the ecliptic, or too much depressed below it, for her disk to touch the earth’s shadow at full, or for her shadow, or her penumbra, to touch the earth’s disk at new. An eclipse, therefore, of either luminary can only take place when they are within their proper limits, or distances, from the nodes or intersections of both orbits. And because the limits of solar eclipses are wider than those of lunar, in general there will be more eclipses of the sun than of the moon. In any year, the number of eclipses of both luminaries cannot be less than two, and these will both be of the sun, nor more than seven: the usual number is four; and it is very rare to have more than six. But though solar eclipses happen oftener, lunar are more frequently observed in any particular place. For an eclipse of the moon is visible to the inhabitants of half the globe at the same instant; whereas, an eclipse of the sun is visible only within that part of the earth’s surface, traversed by the moon’s total shadow, and by her penumbra, or partial shadow. But ...